نتایج جستجو برای: granulite

تعداد نتایج: 412  

2010
Wang-Chun Xu Hong-Fei Zhang Randall Parrish Nigel Harris Liang Guo Hong-Lin Yuan

We present geochronological evidence in the eastern Himalayan syntaxis (Namche Barwa) for high-pressure (HP) granulite-facies metamorphism and explain its importance for understanding both the deep continental subduction of the Indian plate beneath Asia and its subsequent exhumation. The timing of peak and retrograde metamorphism in part constrains these processes but is debated. We present zir...

2001
J. S. Daly K. de Jong P. Guise S. Bogdanova D. Bridgwater

The Lapland–Kola Orogen (LKO; former Kola craton) in the northern Fennoscandian Shield comprises a collage of partially reworked late Archaean terranes with intervening belts of Palaeoproterozoic juvenile crust including the classic Lapland Granulite Terrane. Rifting of Archaean crust began at c 2.5–2.4 Ga as attested by layered mafic and anorthositic intrusions developed throughout the norther...

2000
Andreas Möller Klaus Mezger Volker Schenk

U–Pb monazite and zircon ages reveal that the high pressure granulites from eastern Tanzania were metamorphosed during a Pan-African tectonothermal episode. These mineral ages range from 610 to 655 Ma and indicate that peak metamorphic conditions were diachronous in the different granulite domains. U–Pb titanite and rutile ages define integrated cooling rates of 2–5°C/Ma for all investigated gr...

2006
K. H. MAHAN P. GONCALVES M. L. WILLIAMS

The Legs Lake shear zone is a crustal-scale thrust fault system in the western Canadian Shield that juxtaposes high-pressure (1.0+ GPa) granulite facies rocks against shallow crustal (< 0.5 GPa) amphibolite facies rocks. Hangingwall decompression is characterized by breakdown of the peak assemblage Grt + Sil + Kfs + Pl + Qtz into the assemblage Grt + Crd + Bt ± Sil + Pl + Qtz. Similar felsic gr...

2010
Michael Brown

a r t i c l e i n f o Keywords: Eclogite HP granulite Paired metamorphic belts UHPM UHTM The modern plate tectonics regime is characterized by a duality of thermal environments, one representing the subduction zone and the other representing the arc–backarc or orogenic hinterland. This duality is the hallmark of one-sided (asymmetric) subduction, and the characteristic imprint of one-sided subd...

2005
I. ROELANDTS Jo M. DELBROUCK J. C. DUCHESNE

More than 200 specimens from different occurrences of the Rogaland igneous complex and surrounding granulite facies metamorphic rocks (S. W. Norway) have been analysed by a direct non-destructive proton induced gamma-ray emission (PIGE) technique. The fluorine contents vary from < 25 ppm to 3500 ppm. There is a good correlation between the concentration of fluorine and that of phosphorus for ig...

Journal: :Anais da Academia Brasileira de Ciencias 2008
Léo A Hartmann Dunyi Liu Yenbin Wang Hans-Joachim Massonne João O S Santos

U-Pb dating of zircon was undertaken with the Beijing SHRIMP II (sensitive high resolution ion microprobe) on anamphibolite facies granodiorite and an almandine-albite granulite from the Santa Maria Chico Granulitic Complex, southern Brazilian Shield. This work was also done to unravel protolith ages which are often hidden in the array of partly reset data. The obtained metamorphic ages of the ...

2004
R. T. Pidgeon

Four metasedimentary zircon populations from different tectonometamorphic units of the Central and the Northern Schwarzwald (Variscan belt, SWGermany) were investigated using SEM, cathodoluminescence and SHRIMP dating. Despite partially strong modifications of primary internal morphologies during Variscan metamorphism at amphibolite (750 C, 0.4– 0.6 GPa) and granulite-facies conditions (950–1,0...

2017
Kiara L. Alessio Martin Hand Laura J. Morrissey David E. Kelsey Justin L. Payne

Phase equilibria modelling incorporating melt reintegration offers a methodology to create hypothetical rock compositions that may have existed prior to melt loss, allowing the potential prograde evolution of rocks to be explored. However, melt reintegration modelling relies on assumptions concerning the volume of melt that was lost and is generally restricted by the absence of direct constrain...

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